Method and tool for producing a flange on a bush bearing

ABSTRACT

The invention relates to a method for producing at least one axial flange on an elastomer bush bearing. According to the invention, the axial flange(s) is/are produced by flanging one or both axial ends of the outer sleeve of the pre-assembled bearing after the bearing has been assembled. During this assembly process the inner component is inserted with the elastomer bearing body into the outer sleeve. In the tool, which is provided for this method and which can be used on a press, the force induced by the compressive force is transferred to both axially acting and radially acting deformation elements. Therefore, at least one of the axially acting deformation elements exhibits a groove, which is located on the side facing the bush bearing and by which the respective axial end of the outer sleeve of the bearing is held, whereas the radially acting deformation elements exhibit on their side that is immediately adjacent to the deformation element with the groove, a projection, which projects radially towards the inside.

The invention relates to a method for producing at least one axialflange on an elastomer bush bearing. Furthermore, the subject of theinvention is a tool that is appropriate for carrying out the method. Theinvention relates preferably to the production of a dual flange, thus toproduce an axial flange on both axial ends of a bush bearing.

Elastomer bush bearings, as used in large numbers chiefly in theconstruction of vehicles, for example, in the area of the wheelsuspension, are often equipped with an axial flange on one side or onboth sides. Bearings of the type noted in the preamble of the claimcomprise a substantially cylindrical inner component; an elastomerbearing body, which envelops the inner component and is connected tosaid inner component by means of vulcanization; and an outer sleeve,which accommodates the inner component with the bearing body. Optionallythe outer sleeve is also connected by vulcanization to the elastomerbearing body. The axial flange(s) is/are formed by flanging the outersleeve of the bearing. When the bearing is assembled at the installationsite for the intended use, the axial flanges serve as a bearing surface,which results in a reduction in the axial pressure per unit area thatacts on the bearing.

During the production of the bearing, its elastomer bearing body isradially compressed in order to set a predetermined radial rigidity.That is, a prestress is produced in the elastomer of the bearing body.To this end, following vulcanization of the bearing, or rather after theinner component was mounted with the bearing body in the outer sleeve,the diameter of the cylindrical outer sleeve is decreased in adeformation process. In this context one also talks about a calibrationof the bearing.

To assemble the bearing at the installation site for the intended use,the bearing is generally pushed with its outer sleeve into a receivingeye, provided for the same, and is screwed through the hollowcylindrical inner component. However, to the extent that at this stageboth sides of the bearing exhibit, as is often necessary and/or desired,an axial flange, there is the problem that the bearing may no longer beeasily inserted into the receiving eye, intended for this purpose,because its outside diameter on both axial ends is larger, owing to theaxial flanges constructed there, than the inside diameter of thereceiving eye. One possibility for solving this problem lies inconstructing the bearing in the axial direction in two parts, insertingeach half of the bearing from the side into the bearing eye andconnecting them together in the same operation. Of course, from a costpoint of view it is considered a drawback that in this case the bearingpoint needs two parts to realize one bearing.

The DE 10 2005 029 614 describes a solution for the aforementionedproblem that avoids this drawback. After the inner component and thebearing body have been assembled in the outer sleeve or rather afterthey are connected to the outer sleeve below the flanges constructed onthe axial ends of the sleeve, a crimp is put into the outer sleeve. Inthe course of inserting this crimp, the outer edge of the flangingforming the flange is moved radially toward the inside, so that theoutside diameter of the axial flange is reduced. If the depth of thecrimp is suitably dimensioned, the outside diameter of both axialflanges is preferably decreased so far that the bearing may be easilyinserted into a receiving eye.

The solution presented in the aforementioned document also assumes, likethe state of the art that was known prior to the filing of thisapplication, that the flangings on the outer sleeve for forming theaxial flanges already exist before the inner component is inserted withthe bearing body into the outer sleeve. Suitable outer sleeves with thealready constructed flangings are purchased from the suppliers as aso-called collar bush. The supplier produces the flangings on therespective tubular segments, which are subsequently provided for formingthe outer sleeves, with the use of a deep drawing process. This in turncauses the manufacturer of bush bearings to incur higher costs for theprocurement of materials.

The object of the invention is to provide a solution, by means of whichaxial flanges may be easily constructed on a rubber bushing and thecosts for the procurement of materials may be reduced. To this event amethod and a suitable tool for carrying out the method shall bedisclosed.

The problem is solved by means of a method having the features disclosedin the main claim. A suitable tool for solving the problem and carryingout the invention is characterized by the first claim relevant to theobject. Advantageous embodiments and/or further developments aredisclosed in the respective dependent claims.

The method that is proposed for producing one axial flange or two axialflanges on an elastomer bush bearing relates to a bush bearing of theconventional construction. Such a bearing comprises, as stated above inthe introductory part of the specification, a substantially cylindricalinner component; an elastomer bearing body, which is connected to saidinner component by means of vulcanization; and an outer sleeve, whichaccommodates the inner component with the elastomer bearing body. Theaxial flanges are formed on this bearing as a surface segment, whichenvelops one or both axial end(s) of the outer sleeve and projects inthe outward direction. In contrast to the prior art, however, theconstruction of the axial flange(s) is carried out, according to theinvention, after the assembly of the bearing, thus, after the innercomponent was inserted with the elastomer bearing body into the outersleeve and after the bearing body was connected, if desired, to saidouter sleeve by means of vulcanization. Therefore, the axial flange(s)is/are produced, according to the invention, by flanging one or bothaxial end(s) of the outer sleeve of the bearing that is alreadypre-assembled.

According to a preferred embodiment of the invention, the processingsteps are arranged in such a manner that the flanging of the outersleeve for the purpose of producing the axial flange(s) is carried outsimultaneously with the calibration of the bearing. That is, theflanging of at least one of the axial ends of the outer sleeve of thebush bearing is carried out in a joint working step with thecalibration, during which the diameter of the outer sleeve is reduced atleast in the area of the axial end(s), on which an axial flange isproduced.

The production of the bilateral axial flanges is carried out, accordingto a planned arrangement of the method, in such a manner that theoutside diameter of the flangings forming the axial flanges is decreasedin conjunction with the simultaneous calibration. To this end a crimp isput, according to the DE 10 2005 029 614, into the outer sleeve belowthe axial flanges.

In the course of affixing the crimp the axial flanges are pulled, inmanner of speaking, radially towards the inside. In so doing, the depthof the corresponding crimps is dimensioned in such a manner that theoutside diameter of the flangings is decreased to a size that is lessthan the inside diameter of a receiving eye that is provided forreceiving the bush bearing.

The method, according to the invention, may be applied advantageouslyeven to hydro bushings, wherein the elastomeric bearing body in the areaof at least one of its axial ends exhibits at least two chambers, whichare connected together by means of an overflow or throttle channel andare intended for a viscous damping agent. Therefore, the axial flangesmay be produced in one working step, the bearing may be calibrated, andthe radial stop abutments may be constructed in the damping agentchambers. Said chambers are used to limit in a defined manner the radialidle travel of the elastomer through the chambers in order to prevent anoverstressing or even a destruction of the elastomer bearing body.

The suitable tool for solving the problem or rather for carrying out themethod, according to the invention, and for producing at least one axialflange in a bush bearing is a tool for a press. Therefore, depending onthe construction of the press, the tool is clamped, as a tool head, intothe press and is subjected to a compressive force via a stamp of thepress. Following the basic approach to the solution, the bush bearing,comprising an inner component, a bearing body and an outer sleeve, isput into a working chamber of the tool as a pre-assembled bearing orrather vulca component in order to produce one or two axial flange(s).In addition, the tool exhibits at least one force transfer element.Owing to this force transfer element, the force, induced by thecompressive force acting on the tool, is transferred almostsimultaneously to both the deformation element acting axially and aplurality of deformation elements acting radially on the outer sleeve ofthe bearing. The radially acting deformation elements are disposedaround the periphery of the bush bearing accommodated by the workingchamber. To produce at least one axial flange, at least one of theaxially acting deformation elements, which during the pressing proceduremove towards each other in the direction of the bearing axis of theprocessed bush bearing, thus following it, exhibits a circumferentialgroove on its side facing the bearing. The width of this groove isequivalent to at least the width of the flange, to be constructed on thebush bearing. In addition, the geometry of the axially actingdeformation element, which is provided with the groove, is designed insuch a manner that during the deformation or rather the pressingprocedure, the inner edge of the groove rests against the inside wall ofthe outer sleeve of the bearing that projects into the groove. Theradially acting deformation elements, which during the pressingprocedure move radially towards each other on the bearing axis of theprocessed bush bearing between the axially acting deformation elements,along which said radially acting deformation elements slide, areconstructed in such a manner that they exhibit a projection, projectinginto the interior of the working chamber, in the areas, immediatelyadjacent to the axially acting deformation element(s), which areprovided with the groove. During the pressing procedure, this projectionis pressed, adjacent to the areas, projecting into the grooves, into theouter sleeve of the bush bearing. The result of the projections of theradially acting deformation elements that project into the outer sleeveof the bearing, on the one hand, and the force, acting simultaneouslyvia the axially acting deformation elements, on the other hand, is thatduring the pressing procedure the areas projecting into the grooves areflanged radially in the outward direction so as to form a flange.

In a preferred embodiment of the tool, according to the invention, oneor more spring(s) is/are disposed between the force transfer elementsand an axially acting deformation element. Thus, it is achieved that theforce, resulting from the compressive force, is transferred from theforce transfer element at the start of the pressing procedure to therespective, axially acting deformation element, whereas the forcetransfer to the radially acting deformation elements does not startuntil later. This prevents the bush bearing from being pushed upward andtilted by the radially acting deformation elements at the start of thepressing procedure, an effect that could result in its outer sleevebeing crushed.

In accordance with an optional embodiment of the inventive tool, theforce transfer to the radially acting deformation elements is caused bythe complementary contours of the force transfer elements and of theradially acting deformation elements sliding past one another. Theinventive tool ought to exhibit at least 6 radially acting deformationelements, which are uniformly distributed on the periphery of a bushbearing accommodated by the working chamber. For an optimal calibrationof the bearing and in light of an outer bearing contour that is asuniform or rather as flat as possible, the tool is equipped preferablywith 12 radially acting deformation elements.

The invention shall be explained in detail below once again with the aidof an embodiment. In the associated drawings:

FIG. 1 depicts an elastomer bush bearing prior to producing the axialflanges

FIG. 2 depicts a tool used to produce the bilateral axial flanges

FIG. 3 depicts a bush bearing comparable to the bearing, according toFIG. 1, after the bilateral axial flanges have been produced by means ofthe tool, according to FIG. 2.

FIG. 1 depicts the standard design of an elastomer bush bearing. Thebearing comprises a metallic, substantially cylindrical inner component1; an elastomer bearing body 2, surrounding the inner component 1; andan outer sleeve 3, receiving the aforementioned components. Asemphasized above, the inner component 1 of the bearing is substantiallycylindrical, but exhibits in the illustrated example a varying outsidediameter. Therefore, the outside diameter of the inner component 1 isslightly enlarged in the central area of its axial reach. Such a shapingis basically known for realizing specific radial characteristics. Theinner component 1 is connected to the bearing body 2 by means ofvulcanization and inserted into the outer sleeve 3. Depending on theintended purpose, the outer sleeve 3 may also be connected, if desired,to the bearing body 2 by means of vulcanization. As one can see, thebush bearing, depicted in FIG. 1, does not exhibit yet any of the axialflanges 4, 4′, after the components of said bush bearing have beenassembled. Contrary to the prior art flanges, these flanges shall berealized with a tool, which is reproduced in FIG. 2, only afterassembly.

The tool, depicted in FIG. 2, is a rotationally symmetrical tool for apress, which, depending on the construction of the press, is received,as a tool head, by the press or rather is clamped into the press and issubjected to a compressive force by means of a stamp of the press forthe purpose of producing axial flanges 4, 4′ on the bush bearing placedin the tool. The tool comprises in essence a base plate 14; a bottompressure pad 8′; a plurality of pushers 9 ₁-9 _(n), which are disposedin a circular course around a bush bearing to be placed in the workingchamber 10; an upper pressure pad 8; and a bell 7, by means of which thetool can be connected to the press or rather effectively linked. Owingto the sectional view in FIG. 2, basically only two of the pushers 9 ₁-9_(n) can, in fact, be seen, whereas the spatial configuration of therest is indicated only by dashed—dotted-lines. Within the meaning of theabove presentation of the inventive tool, the bell 7 is a force transferelement, which transfers the force, corresponding to the compressiveforce, to the deformation elements: that is, the pressure pads 8, 8′, asthe axially acting deformation elements, and the pushers 9 ₁-9 _(n), asthe radially acting deformation elements. Compression springs 17, 17′are disposed between the bell 7 and the upper pressure pad 8. Inaddition, there is a so-called guide plate 16 above the base plate 14.The radially external areas of the pushers 9 ₁-9 _(n) are guided in saidguide plate. This guide plate 16 prevents the pushers 9 ₁-9 _(n), whichare constructed moveably in the radial direction, from falling out ofthe tool, for example, when the tool is moved.

FIG. 2 shows the tool without a bush bearing, to be processed with theaid of the tool. At the same time the position of the axis 6 of a bushbearing, to be placed in its working chamber 10, is marked for the sakeof a better orientation in the drawing. The operating principle of thetool is as follows. To insert a bushing to be provided with axialflanges 4, 4′, the bell 7 is moved to the top. The pushers 9 ₁-9 _(n),which were previously held together by the bell 7 (that is, were forcedradially towards the inside), are moved radially towards the outside bythe force of the springs 15 ₁-15 _(n), which are only indicated here, asfar as the stop abutments, which are formed by the guide plate 16. Inthis way they release the interior or rather the working chamber 10 ofthe tool for the purpose of inserting an elastomer bush bearing,according to or similar to FIG. 1.

After insertion of the bush bearing, the bell 7 is brought down again;and thereafter, compressive force is applied. At the same time the bushbearing lies in such a manner in the tool that the outer sleeve 3 of thebearing comes to rest with the insides of its axial ends against theinside edges 12, 12′ of the grooves 11, 11′ in the top and the bottompressure pad 8, 8′. When the bell 7 is pushed down by the press, itsinside contour, which slopes radially towards the outside, slides alonga complementary outer contour of the pushers 9 ₁-9 _(n). Therefore, thepushers 9 ₁-9 _(n) are moved gradually radially towards the insideagainst the spring force of their springs 15 ₁-15 _(n) and thus slidewith their axial outer edges along the pressure pads 8, 8′. In so doing,the projections 13 ₁-13 _(n), 13 ₁-13 _(n), which are constructed at thetop and the bottom on the pushers 9 ₁-9 _(n), push at the top and thebottom into the outer sleeve 3 of the elastomer bush bearing belowand/or above the axial ends, resting in the grooves 11, 11′. Thus, onthe basis of the force, acting axially on the bearing simultaneously viathe upper and the bottom pressure pads 8, 8′, the areas, which arelocated in the grooves 11, 11′ and belong to the outer sleeve 3 of thebush bearing, are bent radially towards the outside in the manner of asharp edge or rather are flanged so as to form an axial flange 4, 4′.Owing to the projections 13 ₁-13 _(n), 13′₁-13′_(n), which areconstructed on the pushers 9 ₁-9 _(n), and the 5, 5′, which are affixedin the outer sleeve 3 and are adjacent to the axial flanges 4, 4′ owingto said projections, the axial flanges 4, 4′ are pulled radially towardsthe inside in the next phase of the pressing procedure, so that thisprocess decreases their outside diameter D. If the flanges 4, 4′ and theprojections 13 ₁-13 _(n), 13′₁-13′_(n) and/or the crimps 5, 5′, producedin the outer sleeve of the bearing, are suitably dimensioned, the resultis a decrease in the outside diameter D of the axial flanges 4, 4′ sothat despite the fact that the axial flanges 4, 4′ are produced on bothsides, the bearing may be easily inserted into a receiving eye, providedfor its accommodation at the installation site.

FIG. 3 shows a bush bearing comparable to the bearing, according toFIG. 1. The inner component of the bearing, the shape of which isconstructed somewhat differently, is not supposed to be the subject of acloser inspection, but is also to be regarded as substantiallycylindrical in the context of the above explanations. Even in the caseof this bearing, the axial flanges 4, 4′ are produced only after theinner component, the bearing body and the outer sleeve have been joinedtogether. When the deformation procedure, presented within the scope ofthe explanations with respect to FIG. 2, has ended, the elastomer bushbearing, which is basically comparable to the bearing, according to FIG.1, exhibits the construction, shown in FIG. 3.

REFERENCE NUMERALS

1 inner component

2 bearing body

3 outer sleeve

4, 4′ axial flange

5, 5′ crimp

6 bearing axis

7 force transfer element (bell)

8, 8′ axially acting deformation element (pressure pad)

9 ₁-9 _(n) radially acting deformation element (pusher)

10 working chamber

11, 11′ groove

12, 12′ inside edge of the groove

13 ₁-13 _(n) projection

13′₁-13′_(n) projection

14 base plate

15 ₁-15 _(n) spring

16 guide plate

17-17′ spring

1. Method for producing at least one axial flange on an elastomer bushbearing, which comprises a substantially cylindrical inner component anelastomer bearing body, which envelops the inner component and isconnected to said inner component by means of vulcanization; and anouter sleeve, which accommodates the inner component with the elastomerbearing body, whereby the axial flange is/are formed as a surfacesegment, which envelops an axial end of the outer sleeve andproject/projects radially towards the outside, characterized in thatafter the assembly of the bearing, during which the inner component isinserted with the elastomer bearing body into the outer sleeve, theaxial flange is/are produced by flanging the axial endes of the outersleeve of the pre-assembled bearing.
 2. Method, as claimed in claim 1,characterized in that the outer sleeve of the bearing is also connectedto the elastomer bearing body by means of vulcanization.
 3. Method, asclaimed in claim 1, characterized in that the flanging of the outersleeve for the purpose of producing the axial flange is carried out inone joint working step, with the bearing calibration, which serves togenerate a prestress in the bearing body, and during which the diameterof the outer sleeve is reduced at least in the area of the respectiveaxial end, to be provided with an axial flange.
 4. Method, as claimed inclaim 1, characterized in that when the bearing is calibrated in thecourse of producing the axial flange, the diameter of the outer sleeveis reduced by affixing a crimp below the axial flanges, thus alsodecreasing the outside diameter of the flangings of the outer sleeve forforming the axial flanges.
 5. Method, as claimed in claim 4,characterized in that the outside diameter of the flangings is decreasedto the extent that it is less than the inside diameter of a receivingeye that is provided for receiving the bush bearing.
 6. Method, asclaimed in claim 3, for producing at least one axial flange for a bushbearing, whose elastomer bearing body exhibits at least two chambers,which are connected together by means of an overflow or throttle channeland which are intended for a viscous damping agent, in the area of atleast one of its axial ends, characterized in that radial stop abutmentsare formed in the course of producing the axial flange and thesimultaneous calibration of the bearing in its chambers.
 7. Tool forproducing at least one axial flange on a bush bearing by means of apress; said tool comprising a working chamber, which receives a bushbearing, comprising an inner component, a bearing body and an outersleeve; axially active deformation elements and radially activedeformation elements; and at least one force transfer element, by meansof which a force, induced by a compressive force acting on the tool, istransferred to the axially acting deformation elements and the radiallyacting deformation elements, which are disposed around the periphery ofa bush bearing accommodated by the working chamber, whereby at least oneof the axially acting deformation elements, which during the pressingprocedure move towards each other in the direction of the bearing axisof the processed bush bearing, exhibits a circumferential groove on theside facing the bush bearing, the width of this groove being equivalentto at least the width of the axial flange to be constructed on the bushbearing; and the inside edge of said groove resting on the inside wallof the outer sleeve of the bearing that projects into the groove; andwhereby in the areas immediately adjacent to the axially actingdeformation elements, provided with the groove, the radially actingdeformation elements, which move during the pressing procedure betweenthe axially acting deformation elements, sliding along these deformationelements, radially in the direction of the bearing axis of the processedbush bearing, exhibit a projection, which projects into the interior ofthe working chamber and which during the pressing procedure is pressed,adjacent to the areas, projecting into the grooves, into the outersleeve of the bush bearing, so that the areas of the outer sleeve thatproject into the grooves, are flanged in the outward direction so as toform an axial flange.
 8. Tool, as claimed in claim 7, characterized inthat one or more springs are disposed between the force transfer elementand an axially acting deformation element, whereby the compressionforce, is transferred from the force transfer element at the start ofthe pressing procedure to the respective, axially acting deformationelement, and whereas the force transfer to the radially actingdeformation elements does not start until later.
 9. Tool, as claimed inclaim 7, characterized in that the compressive force is transferred tothe radially acting deformation elements by the complementary contoursof the force transfer element and of the radially acting deformationelements sliding past one another.
 10. Tool, as claimed in claim 7,characterized in that said tool exhibits at least 6 radially actingdeformation elements, which are uniformly distributed on the peripheryof a bush bearing accommodated by the working chamber.
 11. Tool, asclaimed in claim 10, characterized in that said tool exhibits 12radially acting deformation elements.